“James is going to decide that he can no longer sit back and be a sidekick, so he’s going to decide to become a vigilante,” the executive producer teased. “He’s going to become Guardian, complete with the shield — which is going to cause a massive problem in his relationship with Kara, because he has decided not to tell her.”

The newest masked vigilante brings “Supergirl” closer in tone to her new CW channel-mates on “Arrow” and “The Flash,” and will introduce the similar dilemma of what makes a vigilante a hero and not a criminal, particularly in the titular superhero’s mind.

“Now there’s this new masked vigilante, and [Kara] has her own feelings about vigilantes,” Kreisberg said. “It becomes a push and pull of who gets to decide who gets to be the hero.”

Kreisberg also discussed the sudden dissolution of the Kara-James romance, which had a heavy buildup in Season 1, admitting creatively, it wasn’t where the writers wanted it to be.

“We felt like we were pursuing that relationship more because we felt like we had to than any of us was really, truly feeling it,” he said. “It was interesting because we brought in some new writers in the middle of the season, to get some fresh blood going, and even they — coming at it fresh — sort of felt like we weren’t quite sure how we were going to make [the relationship] happen. We realized that the best scenes between them were just the nice, sweet scenes when they were just being friends.”